Pressurized fluid insulation for high voltage cable

ABSTRACT

An electrical connection for high votlage insulated cable, either to a cable termination or to a second cable is provided with a hollow tubular sleeve of resilient elastomeric insulating material which surrounds the insulated end portion of one or more cables. The sleeve is surrounded by a rigid shell or casing and contains an insulating fluid under elevated pressure provided to cause the inner surface of the sleeve to engage under elevated pressure in surface-to-surface contact with the exterior surface of the end portion of the insulation provided at the end or ends of the cable or cables.

United States Patent 1191 Mashikian 1 Apr. 8, 1975 PRESSURIZED FLUIDINSULATION F0 3.544.700 12/1970 Priaroggia 174/21 R x HIGH VOLTAGECABLE1 3,737,556 6/1973 Cunningham 174/19 [75] Inventor: Matthew S.Mashikian, Huntington Woods, Mich.

[731' Assignee: The Detroit Edison Company,

Detroit, Mich. 221 Filed: Feb. 1, 1974 [21] Appl. No.: 438,575

[52] US. Cl. 174/19; 174/73 R; 339/117 P; 174/21 R [51] Int. Cl. H02q15/22 [58] FieldofSearch 339/117 R,1l7 P,118 R, 339/136 R, 137, 149 R,150 R, 150 C, 151 R, 151 C, 200 R, 201, 206 R,210 R, 213 R, 213 T,217R,217 PS; 174/19,21 R,21 C, 73 R [56] References Cited UNITED STATESPATENTS 3,538,241 11/1970 Rein 174/73 R Primary Examiner-Roy LakeAssistant Examiner-DeWalden W. Jones Attorney, Agent, orFirm-Whittemore, Hulbert & Belknap 57 ABSTRACT- An electrical connectionfor high votlage insulated cable, either to a cable termination or to asecond cable is provided with a hollow tubular sleeve of resilientelastomeric insulating material which surrounds the insulated endportion of one or more cables. The sleeve is surrounded by a rigid shellor casing and contains an insulating fluid under elevated pressureprovided to cause the inner surface of the sleeve to engage underelevated pressure in surface-to-surface contact with the exteriorsurface of the end portion of the insulation provided at the end or endsof the cable or cables.

33 Claims, 10 Drawing Figures PATENTEBAFR 81975 SHEET 1 BF 4 I ill I my?FIGS PATENTEBAPR a 1915 SQU 3 OF 4 HEB APR 8 1915 sumuqgd BRIEF SUMMARYOF THE INVENTION In providing a connection to the end of a high voltageinsulated conductor, either to a terminal fitting or to the end portionof the conductor of a second cable, a problem has been presented inobtaining a proper surface-to-surface contact between an insulatingsleeve provided to surround the end portion of insulating materialadjacent the end of the cable or cables, and the outer surface of theinsulation adjacent the end of the cable. I

Where the insulating material is in the form of a resilient elastomericfiller, it has been difficult to provide adequate compression when thecable expands and contracts as a result of its daily and seasonal loadcycle. Another disadvantage of this kind of cable termination (orconnection) lies in the difficulty experienced in installing it. Thedifficulties in employing a fluid (liquid or gas) insulating mate rialwith or in place of the elastomeric material, with accompanying problemsof sealing against leakage, are obvious.

In accordance with the present invention the insulating material is inthe form of a sleeve which surrounds the end portion of the cable and isformed of a resilient elastomeric insulating material such for exampleas butyl or silicone rubber, or polyurethane, and is so shaped as to behollow, or in other words, to be provided with an annular interiorcavity. In use, this sleeve is received in a rigid shell which inaccordance with the particular type of connection employed, may eitherbe a metallic shell or it may be a rigid insulator body. The hollowinterior of the sleeve is charged with an insulating fluid, either gasor liquid, at an elevated pressure sufficient to provide for inwarddisplacement of the inner wall of the sleeve into a firm continuoussurfaceto-surface pressure contact with the outer surface of the endportion of the insulation adjacent the bared end of the conductor of thecable. Silicone or polybutene oil are examples of suitable insulatingliquids, and sulfur hexafluoride, nitrogen and freon are examples ofsuitable insulating gases.

In general terms, the invention may be applied to a cable termination inwhich the bared end of the conductor may be suitably connected to anexterior fitting. Alternatively, the construction may be in the natureof a connection or joint between the ends of two sections of highvoltage cable, in which case the ends of the conductors of the cablesare bared and electrically connected together by conventional means,after which the connection between the conductors as well as the endportions of the insulation surrounding the conductors adjacent the endsof the cables, is surrounded by the hollow tubular insulating sleeve,the hollow interior chamber of which is charged with insulating fluidunder elevated pressure.

Generally, an electrical stress reliefelement is provided in contactwith one end of the hollow tubular sleeve. For this purpose the end ofthe hollow tubular sleeve remote from the bared conductor end of thecable is tapered to provide an outer generally conical surface. Thestress relief sleeve is formed of a semiconductor such for example asinsulating resin containing particles of conducting material such forexample as graphite or carbon black particles, and has its inner Isurface tapered into conformity with the outward taper provided at theend of the hollow sleeve. The tapered surfaces are brought into contactand may in fact be permanently bonded together by suitable means. Thereis thus provided a generally conical interface which has the effect ofpreventing localized electrical stress when the connection is carryinghigh voltage current.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectionalview of a simplified embodiment of the present invention applied to acable termination.

FIG. 2 is a longitudinal sectional view of a further embodiment of thepresent invention.

FIG. 3 is an enlarged fragmentary detail of the sleeves.

FIG. 4 is an enlarged sectional view illustrating a modification of thestructure shown in FIG. 2.

FIG. 5 is a longitudinal sectional view of structure in which theinvention is applied to a connection between the ends of two highvoltage cables.

FIG. 6 is a sectional view on the line 66, FIG. 5.

FIG. 7 is a fragmentary view illustrating a modification of a stressrelief sleeve applied to the construction of FIG. 5.

FIG. 8 is a fragmentary sectional viewillustrating a modification of thehollow sleeve and insulation, as illustrated in FIG. 5.

FIG. 9 is an enlarged sectional view of one of the valves providingconnection to the interior of the hollow sleeve.

FIG. 10 is a fragmentary longitudinal sectional view through aconstruction in which a modified form of the present invention isapplied to the connection between two high voltage cables.

DETAILED DESCRIPTION The present invention may be applied to differenttypes of electrical connections such for example as the termination of ahigh voltage cable or the interconnection between the ends of two cablesections. Embodiments of these two different applications of the presentinvention will be described under separate headings below:

CABLE TERMINATION Referring first to FIG. 1 there is illustrated a verysimi ple application of the present invention to a cable termination. Inthis Figure there is illustrated a high voltage electrical cable 10.Cables of this type are ordinarily provided with an external conductingground shield. To apply a terminal connection to such a cable, theshield of the cable is pencilled as indicated at 12, providing a shorttapered section beyond which the conducting shield is removed. Theinsulation of the cable indicated at 14 is stripped away to bare the endof the conductor as indicated at 16. The end portion of the cable isreceived in the hollow interior 18 of an insulator body of usualconfiguration having a metal cap 22 permanently affixed to the outer endof the insulator body. The metal cap includes a tubular portion 24through which the bared end of the conductor 16 extends. A permanentconnection between the bared end of the conductor 16 and the tubularportion 24 of the cap 22 is provided by crimping the tubular portion 24into tight permanent crimped engagement with the bared end of theconductor 16. Electrical connection is made with the cable conductor bymeans of a conventional clamp type connector installed around thetubular portion 24.

The dimension of the elongated generally cylindrical cavity 18 withinthe insulator body 20 is proportioned with respect to the dimension ofthe end portion 14 of the insulation on the cable so as to leave anannular space within the insulator body surrounding the cylindricalinsulation on the end portion 14 of the cable.

The annular space intermediate the end portion 14 of the cable and theinner surface 18 of the insulator body is filled with an assembly madeup of a hollow insulating sleeve 30 having an inner wall 32 and an outerwall 34. The sleeve 30 is closed at its ends'and the hollow interiorannular chamber 36 is filled with an insulating fluid, either liquid orgas. If the fluid is a liquid, a silicone oil, polybutene oil, or thelike may be employed.

If an insulating gas is used, gas such as sulfur hexafluoride, nitrogen,freon and the like may be employed.

These fluids must of course be chemically compatible with the materialforming the hollow insulating sleeve.

Associated with the hollow insulating sleeve 30 is a stress reliefsleeve 40. The stress relief sleeve may be formed of a suitableinsulating polymer such for example as the same material employed toform the hollow insulating sleeve 30 except that it will containconducting particles such as graphite or carbon black in an amount tomake the material of the sleeve 40 a semiconductor having a resistivitynot exceeding 10 ohms X cm.

The end of the hollow sleeve 30 remote from the bared end of theconductor 16 is provided with an outer tapered surface 42 and theadjacent end of the stress relief sleeve 40 is provided with an internaltapered generally conical surface 44 which conforms to the surface 42.The interface between the surfaces 42 and 44 is thus a tapered orsubstantially conical interface which provides stress relief.

The stress relief sleeve 40 may also be hollow and provided with anannular interior chamber 46 which may be separately charged withinsulating fluid, either liquid or gas, as previously described. Thetapered end surfaces 42 and 44 of the sleeve may be impervious or I theymay be provided with openings 47 provided for transfer of the insluatingfluid between the hollow interior of the sleeves 30 and 40.

In the construction as thus far described it is contemplated that thehollow sleeve 30 and the sleeve 40 if it is provided with a hollowinterior, are charged with the insulating fluid and permanently sealedwhen they are fabricated. It will be understood that the material ofwhich the sleeves 30 and 40 are formed is a resilient elastomer such forexample as butyl or silicone rubber. As intially charged with theinsulating fluid at the factory, the sleeve 30, and the sleeve 40 if itis also hollow, are expanded by the fluid contained therein so as to beoversize with respect to the transverse dimensions of the annularchamber defined between the cylindrical interior surface of the cavity18 of the insulator body and the exterior cylindrical surface of theinsulation provided adjacent the end of the cable 10. Accordingly, afterthe sleeves have been inserted in the cavity, the insertion of the endportion of the cable 10 as illustrated in FIG. 1 displaces the innersurface of the sleeve or sleeves outwardly and results in a fullsurface-tosurface contact at a suitably elevated pressure.

In order to insure proper contact between the stress relief sleeve 40and to control the pressure conditions existing in the fluid filledhollow sleeve 30, an adjustable closure 50 is carried at the inner endof the insulator body 20 and is adapted to bear against the outer end ofthe stress relief sleeve 40. Screws indicated at 52 are provided forattaching the closure 50 to the insulator body 20 and may be adjusted toapply the desired pressure to the sleeves 30 and 40.

Referring now to FIG. 2 there is illustrated a second embodiment of thepresent invention. In this case the end portion of the cable isindicated generally at 56 and is pencilled as indicated at 58 so thatthe end portion 60 has an outer cylindrical surface formed of insulatingmaterial from which the conducting shield indicated at 62 has beenremoved.

The structure illustrated in FIG. 2 is a cable termination and theinsulation 60 is stripped from the end of the cable to bare a portion ofthe conductor as indicated at 64. The end portion of the cable 56 isreceived in an insulator body 66 including an end closure portion 68having an aperture through which the bared end 64 of the conductor ofthe cable extends. Exterior of the insulator body 66 there is provided aconnector cap 70 having a tubular portion 72 which is crimped orotherwise suitably secured to the end of the conductor. In assembly theenlarged head of the connector 70 engages an O-ring 73 provided in anannular groove 74 at te end of the insulator body.

Surrounding the end portion of the cable is a hollow insulating sleeveindicated generally at 76 having an inner cylindrical wall 78 in fullsurface-to-surface contact under elevated pressure conditions with thecylindrical surface of the insulation 60 at the end of the cable. Thesleeve 76 includes an outer cylindrical wall 80 engaging the innercylindrical surface 82 of the insulator body 66.

The hollow interior 84 of the sleeve 76 is connected to a valve 86extending through the end wall 88 of the sleeve, the valve including anO-ring seal 90 and a removable cap 92. A second valve 94 is providedwhich may be identical with the valve 88 and also communicates with theinterior annular chamber 84 within the hollow sleeve 76. The two valvesare provided so that when the insulating fluid is caused to flow intothe annular chamber 84 through one of the valves, the interior chambermay be purged through the other valve.

The end of the hollow insulating sleeve 76 remote from the bared end ofthe conductor 64 is provided with an outer tapered surface 98 which isgenerally conical in shape but which as illustrated is slightly concavein axial section.

Secured to the inner open end of the insulator body 66 is a tubularshell or casing 100 which is longitudinally tapered to have a smallerdiameter adjacent its upper end as illustrated in the Figure. At itsupper end the shell 100 is provided with a flange 102 which is assembledto flange 104 provided at the lower end of the insulator body 66 bysuitable fastening devices such as the screws 106 and the nuts 108. Atits outer end the shell 100 is provided with a second flange 110 bymeans of which it supports an end closure plate 112 through suitableassembly devices such as the screws 114 and the nuts 116.

Located within the shell 100 is the stress relief device or sleeve whichas shown is hollow and provided with an internal annular chamber orpocket 122. The end of the stress relief sleeve 120 adjacent the hollowinsulating sleeve 76 is provided with an internal tapered surface 124whichi's conformed to the tapered surface 98 of the hollow sleeve 76.These tapered surfaces are generally conical but as illustrated, areprovided with a slight longitudinal outwardly concave/convex curvature,respectively.

To interior of the stress relief sleeve 120 is connected to valvingmeans indicated at 94 through which insulating fluid may be introducedinto the annular pocket 122. In the event that the pocket 122 is sealedagainst communication with the pocket 84 provided in the sleeve 80,twosuch valves will be employed, one for introducing fluid under pressureand the other for purging air from the interior. However, it is alsocontemplated that the adjacent wall portions of two sleeves at thetapered ends thereof may be provided with passages 128 so that fluid mayflow between the hollow interiors of the sleeves. In this case of courseit is only necessary to have two valves, one of which communicates withthe interior of the sleeve 120 and the other of which communicates withthe interior of the sleeve 76.

With the parts of the connectorassembled with the end portion of thecable, as illustrated in FIG. 2, the insulating fluid, eitherliquid orgas, may be introduced into the hollow interior or interiors of thesleeves, thus tending to expand the sleeves and to force the inner wallsof the sleeves into firm engagement with the outer surfaces of the endportion of the cable. It will be observed that the stress relief sleeve120 is adapted to engage the portion of the cable provided with theground shield 62, whereas the hollow insulating sleeve 76 engages onlythe end portion of the insulation 60 from which the shielding materialhas been removed by pencilling as indicated at 58.

The introduction of fluid under pressure into the hollow interior tubeof the sleeve 76 and the sleeve 120 insures full perfectsurface-to-surface contact between the interiorsurfaces of the sleeves76 and 120 throughout the entire end portion of the cable 56.

Referring now to FIG. 3, a stress relief device 130 is provided in placeof the stress relief sleeve 120. In this embodiment of the invention theend of the sleeve 130 adjacent the end of the cable is provided with aninner tapered surface 132 conforming to the outer tapered surface 98 ofthe hollow sleeve 76. In this case the stress relief sleeve 130 isformed of a resilient elasto meric material which may be the same as theresilient elastomeric material from which the hollow sleeve 76 is formedexcept it contains conducting particles such as carbon black or graphitein order to increase its conductivity. The tapered surface 132 of thesleeve 130 may be chemically bonded to the tapered surface 98 of thehollow sleeve 76 along the generally tapered interface. In thisembodiment of the invention it will be apparent that when the endclosure plate 112 engages the ,outerend of the sleeve 130, the sleeve130 may be sufficiently elongated so that the closure plate 112 engagesthe end and forces the sleeve 130 inwardly of the tapered shell 100,thus causing the sleeve 130 to exert an inward pressure on the cableinsulation as the closure plate 112 is tightened by means of the screws114 and nuts 116.

Referring now to FIG. 4 there is shown a different embodiment of theinvention in which the structure shown in FIG. 4 is substituted for thestructure located within the tapered shell 100. In this construction thecable 56 is pencilled as indicated at 58 to expose the insulation 60,leaving the shield 62 in place. In this embodiment of the invention themetallic shell 136 is tapered as shown with the small end of the shelllocated at the top of the Figure. The shell is provided with ears 138having tapped openings 140 for the reception of screws adapted to securethe shell 136 to flanges such as those illustrated at 104 provided atthe lower end of the insulator body 66. As in the embodiment of theinvention illustrated in FIG. 2, the construction includes a stressrelief structure comprising a resilient semiconducting sleeve 142 whichmay be formed of an elastomeric resilient insulating material providedwith particles of graphite or carbon black to produce a resistivity notexceeding 10 ohms X cm.

The outer surface 144 of the sleeve is tapered and conforms generally tothe taper of the shell 136. The inner surface of the sleeve 142 includesa generally conically tapered surface 146 seen at the upper end of theFigure, while the inner surface 148 at the lower end of the sleeve 144is generally cylindrical. In addition, the length of the sleeve 142 issuch that in initial assembly the lower end 150 of the sleeve extendsoutwardly from the flange 152 provided at the lower end of the shell136. An end closure plate 154 is provided having a central opening 156through which the cable 56 extends and the plate is adapted to beattached to the flange 152 by suitable fastening means such for exampleas the screws 158 and nuts 160. With this arrangement, when the plate154 is drawn toward the flanges 152 it applies compressive force to thesleeve 144 and, due in part to the tapered shape of the sleeve, producesradially inward pressure of the sleeve against the portions of the highvoltage cable 56 therewithin.

In this embodiment of the invention there is provided a hollowinsulating sleeve 162 which may be formed of the same material as thesemi-conducting sleeve 144 except that this hollow sleeve does notinclude conducting particles and is fully insulating. The hollow sleeve162 has a tapered outer surface 164 which conforms to the taper of thesurface 146 of the sleeve 144 and is adapted to be engaged in fullsurface-to-surface pressure contact therewith in the assembledconnector. The hollow interior of the sleeve 162 thus provides anannular chamber 166 adapted to receive insulating fluid, either liquidor gas, under elevated pressure, so as to insure full surface-to-surfacepressure contact between the inner surface of the hollow sleeve 162 andthe outer surface of the cable insulation 60. The interior chamber 166of the hollow sleeve 162 is provided with suitable valve means such asindicated at 168 and 170 so that the insulating fluid may be introducedinto the chamber 166 through one of the valves and air initiallycontained therein purged through the other valve.

It will be apparent from a-comparison of FIGS. 2 and 4 that when thestructure of FIG. 4 is substituted for the shell 100 shown in FIG. 2,the surface 146 and 164 provide an interface which is of generallyconical shape establishing a stress relief construction. In this case,the portion of the cable termination received within the insulator body66 may be provided with a hollow insulating sleeve substantially similarto that shown in FIG. 2 except that its lower end will conform to theupper end surfaces of the sleeves 142 and 162.

The constructions illustrated in FIGs. 2 and 4 may be assembled in thefield and after the components are assembled as shown, the annularchambers 84, 122 and 166 will be charged with insulating fluid undersubstantial pressure adapted to maintain full surface-to-surfacepressure contact between the inner surface of the sleeves and theadjacent outer surfaces of the cable through extended use during whichthe cable may undergo repeated expansion and contraction.

CABLE INTERCONNECTION A is illustrated in FIG. 10.

Referring first to FIGS. -9 the construction comprises an enlcosurewhich may be formed of metal and comprises two relatively deepcup-shaped elements .200 provided with flanges 202 which may beinterconnected by suitable means such for example as screws 204 and nuts206. The end or bottom walls of the cups are illustrated at 208 and areapertured as illustrated to receive the ends of high voltage cables 210.The cables include conducting shields 212, pencilled portions 214, andend portions from which the conducting shields have been removed toexpose the cable insulation 216.

The conductors are bared as indicated at 218. The bared cable conductorsare interconnected by any conventional means such for example ascompressed conducting sleeves, soldered sleees, welding or the like. Asplit conductor clamp 220 is provided, details of which are best seen inFIG. 6. Referring to this Figure it will be observed that the clampcomprises two portions 222 and 224 each recessed as indicated at 226 toreceive the ends of the bared conductors. The portions 222 and 224 ofthe clamp are interconnected by suitable means such for example asscrews 228 extending through openings 230 in the portion 222 andengaging in threaded openings 232 in the clamp portion 224. Coilcompression springs 234 are porvided between the portions 222 and 224and are compressed as the portions 7 are brought into clampingengagement by the screws Adjacent opposite ends of the cups 200 thereare provided sleeves 236 which as shown, are adapted to bottom againstthe end walls 208 of the cups. The sleeves 236 are formed of resilientelastomeric insulating material such for example as butyl rubber,silicone rubber, or polyurethane, but contain a small quantity ofconducting particles such for example as particles of carbon black orgraphiteso as to render the sleeves 236 semi-conducting. The radiallyinner surfaces 240 at the inner ends of sleeves 236 are tapered asillustrated into generally conical configuration modified to provide thelongitudinal convex configuration illustrated.

Intermediate the semi-conducting sleeves 236 is a hollow insulatingsleeve indicated generally at 242. This sleeve is formed of insulatingresilient elastomeric material such for example as butyl rubber,silicone rubber, or polyurethane, but differs from the material of thesleeves 236 in that no conducting particles are included so that thematerial of the sleeve 242 is fully insulating.

The ends of the sleeve 242 are provided with tapered outer walls 244shaped to conform to the tapered surfaces 240 of the semi-conductorsleeve 236, and in assembly the surfaces 240 and 244 are in fullsurface-tosurface contact and it is contemplated that these surfaces maybe chemically bonded together. In any case, the tapered interfaceprovided by the surfaces 240 and 244 between the semi-conducting sleeve236 and the hollow insulating sleeve 242 constitutes a stress reliefdevice.

It will be observed that the semi-conducting sleeves 236 extend intocontact with the shields on the cables 210. On the other hand, thehollow insulating sleeve 242 terminates adjacent the pencilled portion214 and extends longitudinally of both end portions of the cable wherethe insulation 216 is exposed and across the gap between the ends of thecable insulation where the conductors 218 of the cable are electricallyinterconnected.

The outer surface of the sleeve 242 is provided with a layer 245 ofsemi-conducting material which may be the same material from which thesleeves 236 are composed.

The inner wall of the insulating sleeve 242 is provided at itsmid-section with a thin layer 246 of conducting material which when thejoint is completed is caused to abut against the clamp 220. Theconducting material may be in the form a a resilient elastomercontaining sufficient conducting particles to provide the requisiteconductivity. This layer is just long enough to extend beyond the edgesof the cable insulation 216 in such a way as to eliminate electricalstresses in the void space 248 between the ends of the cable insulation.

Valve means indicated generally at 250 and illustrated in detail in FIG.9 are provided to communicate with the interior annular chamber orpocket 252 provided in the hollow sleeve 242. These valves include valveelements 254 secured by suitable means such for example as threadswithin the interior of the threaded nipples 256. The nipples 256 havethreaded exteriors and adapted to receive sealing caps 258 which areassociated with sealing means such for example as O-rings 260 to providean adequate seal. The valves are provided in pairs so that both may beopen while insulating fluid is introduced into the chamber 252 throughone of the valved openings and air purged from the interior through theother.

Referring now to FIG. 7 there is illustrated a further embodiment of theinvention in which the solid resilient elastomeric sleeves 236 arereplaced by hollow sleeves 262, each provided with an interior annularcavity 264 provided with valve means indicated generally at 260. Thesleeves 262 are formed of semiconducting material as previouslydescribed and include tubular portions 268 which interconnect thesleeves 262 at opposite ends of the assembly and which engage or arebonded to the outer walls 270 of the intermediate hollow sleeve 242. Theinterior annular chamber 252 provided in the hollow sleeve 242communicates with the chambers 264 in the sleeve portions 262 throughsuitable passages 272.

The advantages of this construction are: (a) there is no electricalstress in this conducting portion; therefore, the existence of thesleeve of a check valve presents no voltagerelated problem; (b) owing tothe fluid in the pocket or chamber 264, the conducting portion of thesleeve can be more effectively compressed against the cable insulation216 and the semiconducting shield 212 and also the pencilled portion 9214; and (c) by providing a valve in communication with the chambers 264at opposite ends of the assembly, the purging of air from the pockets orchambers 252 and 264 is facilitated.

Referring now to FIG. 8 there is illustrated a variation in theconstruction of the cable joint. In this case the middle portion of thehollow sleeve, here indicated at 280, is made outwardly convex asillustrated and the semi-conducting layer 282 provided at its innersurface accordingly has the tapered ends 284 to improve the electricvoltage gradient in that portion of the joint and to provide bettercompression against the cable surfaces. In any case, the casing formedby mating cup portions 286 have the walls adjacent the ends thereofcurved in conformity to the curvature of the hollow insulating sleeve asindicated at 288.

It will be understood that while valves andcheck valves are shown forthe purpose of charging the interior ofthe hollow insulating sleeves aswell as the hollow sleeves formed of semi-conducting material, withpressurized insulating fluidin the field, it is also con templatedthatthese annular chambers may be charged in the factory and the sleevespermanently sealed. In this case of course, the check valves will beomitted and the compression of the sleeves will be achieved by forcesdeveloped by drawing the cup-shaped shells 200 together in assemblyafter the electrical connection is established between the .bared endsof the cables and the sleeve or sleeves have been brought into therelative position illustrated in FIG. 5. 1

Referring now to FIG. 10 there is illustrated a joint intended for usewith very high voltage power cables. In this case the cables areillustrated at 300 and include outer shields 302, pencilled portions304, and end portions at which the cable insulation 306 is exposed. Thecable insulation is cut back to bare the ends of the cable conductors308 which are electrically interconnected by conventional means 310. Acapacitive device 312, details of which will subsequently be described,is positioned around the gap 314 between the ends of the cableinsulation 306 in which the conductors 308 are interconnected.

A combination of insulating sleeve and stress relief assembly 313 isprovided and is inserted within the tapered ends of the capacitivedevice 312 as illustrated. Theentire assembly is housed in tworigidmetallic sleeves or cup-shaped members 316 attached to each otherthrough flanges 318 and suitable clamping means such as screws 320 andnuts 322.

The assembly 313 is provided with an annular pocket 324 formed betweeninsulating walls 326 and 328 formed of an elastomeric resilient fullyinsulating material. The outer ends of the pocket 324 are bounded bycurved surfaces 330, which are surfaces-of revolution defining convexlycurved walls having a stress relief function. The outer ends of theassembly 313 are provided by annular portions 332 formed of a resilientel'astomeric essentially insulating material, which however is providedwith conducting particles to render the end portions semi-conducting aspreviously described. It will be understood that the portions 332 may beformed of the sameresilientelastomeric material as the walls 326 and 328which define the longitudinally tapered annular chamber 324, except thatthe walls 326 and 328 do not include the conducting particles and henceare fully insulating.

If desired, the end portions 332 may be provided with internal annularpockets substantially as suggested in FIG. 7.

The pocket 324 provided in the assembly 313 is connected to two valvemeans indicated generally at 334 and 336 through which insulating fluidmay be introduced and the air within the pocket 324 suitably purged.

The capacitive device 312 comprises a specially shaped tubular bodyhaving at opposite ends inwardly tapered recesses 340 for the receptionof the inner tapered ends of the assembly 313 and interconnected by acylindrical through opening 342 which receives the means interconnectingthe ends of the cable conductors. The device is essentially comprised oftwo sets of cylindrical conducting rings 344 aligned on the same axisand embedded in an insulating mass 346 of a suitable material such forexample as electrical grade epoxy. The diameters of the rings 344 areincreased gradually from the center of the device toward its ends. Theinnermost cylindrical wall 348 is designed to be in good electricalconducting contact with the connecting clamp illustrated at 310 in FIG.10. The outer surface of the device is conducting and may comprise acylindrical metal shell 350. The rings 344 and the innermost cylindricalwall 348 may conveniently be formed of cylindrical metal rings or tubes.

This device will operate to distribute the voltage uniformly along theslanting surfaces of the conical end recesses 340.

With the construction illustrated in FIG. 10 it may be noted that theinsulating structure within each end of the housing completely fills thespace defined by the outer and end walls of the cup portions 316, theouter surfaces of the cables within the housing, and the inclinedtapered surfaces 340 of the recesses at the ends of the voltagedistributor 312. The inner and outer walls of the insulating sleevewhich define the inner and outer limits of the chambers 324, are formedof insulating material. The chambers 324 are further defined by thecurved annular end walls 330'forming a part of the sleeve portion 332.The sleeve portion 332 is also formed of resilient elastomeric materialbut it is rendered semi-conductive by the presence of conductingparticles therein. Accordingly, the curved surface 330 constitutes astress relief cone or device.

Where the annular sleeve 332 is itself provided with an elongatedinternal chamber such as illustrated at 264 in FIG. 7, the entirestructure made up of the sleeves 332 and the chamber walls 326 and 328is expansible to insure that the sleeves completely fill the aforesaidspaces, expelling all air therefrom, and maintaining fullsurface-to-surface pressure contact between the radial inner surface ofthe sleeve assembly and the outer surface of the cable throughout theperiod of service including repeated expansions and contractions of thecable in use.

The voltage distributor specifically illustrated in FIG. 10 isconstituted by a multiplicity of capacitive devices arranged in seriesin which each adjacent ring 344 axially overlaps the adjacent rings andis separated therefrom by dielectric material. With this arrangement itwill be observed that the inner tube 342 is at the voltage of theconductor and the outer tube 350 is at ground potential, assuming thatthe housing 314 and the cable shield 300 are at ground potential.Accordingly, the entire applied voltage is divided between the seriescapacitances as is well understood so that the voltage drop along theinclined conical surface 340 has a uniform gradient.

From the foregoing it will be observed that the common feature presentin all embodiments of the invention is the provision of one or morehollow sleeves formed of insulating or semi-conductive material andprovided with elongated annular chambers for the reception of insulatingfluid at elevated pressure effective to produceessentially radial inwardand outward expansion of the sleeves into full surface-to-surfacecontact with outer restraining surfaces and the radially outer exposedsurfaces of the portions of the cable or cables within the sleeves. Anadditional feature is the division of the sleeve structure into twoseparate components one of which is fully insulating and the other ofwhich is formed of semi-conducting material, the two portions havingtapered or generally conical interfaces forming stress relief cones. Thetwo portions of the sleeves may be provided with separate and separatelychargeable annular recesses or they may be interconnected by passagesproviding for flow of insulating fluid therebetween.

The constructions may be arranged such that the internal annularchambers are permanently charged with insulating fluid under pressure atthe factory and the pressure conditions maintained and controlled by theapplication of external pressure to portions of the sleeve or sleeves bycontaining structure therefor.

Where reference is made to elevated pressure, it is intended to requirea pressure sufficiently above ambient or atmospheric pressure to producethe required surface contact conditions described herein.

. In all cases where the stress relief cone or device such as seen at'40in FIG. 1 or 120 in FIG. 2 is shown as a separate member from sleeves 30or 76, etc., it will be understood that in all cases these may be unitedto form in effect a single element. What I claim as my invention 1. Astress relief connection designed for application to insulated highvoltage electrical cable comprising a hollow tubular sleeve adapted tosurround the insulation adjacent the bared end of an insulated highvoltage electrical conductor and formed of resilient elastomericelectrically insulating material having at the end thereof remote fromthe bared conductor an inwardly tapered exterior surface, a generallytubular stress relief sleeveformed of a material which is at leastsemiconductive having an outwardly tapered interior end surface insurface-to-surface contact with the tapered exterior surface of saidhollow sleeve, a rigid support housing surrounding said hollow sleeve,the interior of said hollow sleeve being an elongated annular chamberadapted to be charged with a pressurized insulating fluid to expand theinner wall of said hollow sleeve radially inwardly to establish intimatecontact between the inner surface of said hollow sleeve and the outersurface of the insulation surrounding the conductor adjacent its baredend.

2. A connection as defined in claim 1 in which said hollow sleeve isprovided with inlet and outlet valves to provide for purging the hollowinterior of the sleeve and to fill the hollow sleeve with fluid underpressure.

3. A connection as defined in claim 1 in which said tubular stressrelief sleeve is formed of resilient elastomeric material and is alsohollow to have an elongated annular chamber to receive insulating fluidunder pressure.

4. A connection as defined in claim 3 in which passages are providedconnecting the hollow interior of said hollow tubular sleeve and thehollow interior of said stress relief sleeve.

5. A connection as defined in claim 1 in which said hollow tubularsleeve is filled with insulating fluid and permanently sealed.

6. A connection as defined in claim 5 in which said connection comprisesan enclosing wall movably associated with said housing, and means formoving said wall relative to said housing to apply pressure to saidhollow tubular sleeve.

7. A connection as defined in claim 1 in which said 'fluid is aninsulating liquid.

8. A connection as defined in claim 1 in which said fluid is aninsulating gas.

9. A connection as defined in claim 1 in which said connection is acable termination, and in which said housing comprises a hollowinsulator body, comprising connector means exposed at the end of saidbody adapted to be electrically connected to the bared end of theconductor.

10. A connection as defined in claim 1 in which said connection is forconnecting the ends of two insulated high voltage cables, comprisingmeans within said hollow tubular sleeve adapted to electrically connectthe bared ends of the conductors, and in which the opposite ends of saidhollow tubular sleeve are both tapered as aforesaid, and stress reliefsleeves as aforesaid are provided at both ends of said hollow insulatedsleeve.

11. An electrical connection comprising in combination a high voltagecable having a conductor surrounded by insulation, the conductor havingan end exposed and extending beyond the end portion of the insulation, arigid housing surrounding the end portion of the insulation, a hollowtubular resilient elastomeric sleeve having an elongated annular chambertherein interposed between the end portion of the insulation and thehousing, said sleeve having at the end thereof remote from the baredconductor a tapered exterior surface, a generally tubular stress reliefsleeve formed of a semi-conductive material having at an end thereof atapered interior surface in surfac-to-surface contact with the taperedexterior surface at said hollow tubular sleeve, an insulating fluid inthe chamber in said sleeve under an elevated pressure sufficient toexpand the chamber defined by the hollow interior of said sleeve toforce the inner wall thereof into firm surface-tosurface contact withsaid insulation.

12. A connection as defined in claim 11 in which said hollow sleeve isprovided with inlet and outlet valves to provide for purging the hollowinterior of the sleeve and to fill the hollow sleeve with fluid underpressure.

13. A connection as defined in claim 11 in which said tubular stressrelief sleeve is also hollow and has an annular chamber to receiveinsulating fluid under pressure.

14. A connection as defined in claim 13 in which passages are providedconnecting the chamber in said hollow tubular sleeve and the chamber insaid stress relief sleeve.

15. A connection as defined in claim 11 in which said hollow tubularsleeve is filled with insulating fluid and permanently sealed.

16. A connection as defined in claim 15in which said connectioncomprises an enclosing wall movably associated with said housing, andmeans formoving said wall relative to said housing to apply pressure tosaid hollow tubular sleeve.

17. A connection as defined inclaim 11 in which said connection is acable termination, and in which said housing is in the form of a hollowinsulator body, comprising connector means exposed at the end of saidbody adapted to beelectrically connected to the bared end of theconductor.

18. A connection as defined in claim 11 in which said connection is forconnecting the ends of two insulated high voltage cables, comprisingmeans within'said hollow tubular sleeve adapted to electrically connectthe bared ends of the conductors, and in which the opposite ends of saidhollow tubular sleeve are both tapered as aforesaid, and stress reliefsleeves as aforesaid are provided at both ends of said hollow insulatedsleeve.

19. An insulated connection between two high voltage cables having endportions in which bared conduc- I tor ends project beyond the ends ofinsulation surrounding the conductors to define a gap between the end ofsaid insulation, connector means in the gap electrically interconnectingthe bared conductor ends, a capacitive voltage distributor comprising anelongated tubular body formed of a dielectric material having elongatedtapered recesses extending into opposite ends and having a centralportion provided with a through opening in which are located the baredconductor ends and the connector means, an inner conducting tube in saidopening in contact with said connector means, an outer elongatedconducting tube covering the outer surface of the voltage distributor, aseries of short circumferentially spaced, axially staggered conductingrings extending along and around each of the tapered recesses, saidrings overlapping adjacent rings and spaced radially of each other, therings being entirely embedded in said dielectric body and having thespaces between adjacent rings being filled with the dielectric materialof said body.

20. A connection as defined in claim 19 which comprises in addition anouter housing formed of conducting material in contact with said outertube.

21. A connection as defined in claim 20 in which said cables haveconducting shields extending into the housing, and means electricallyconnecting said shields to said housing.

22. A connection as defined in claim 21 in which the means connectingthe shields and housing comprise semi-conducting resilient sleeves inthe ends of said housing in surface contact with said shields.

23. A connection as defined in claim 22 in whichsaid semi-conductingsleeves have annular pockets formed therein, and insulating fluid insaid pockets at elevated pressure to expand the sleeves in fullsurface-to-surface contact under pressure with the inner surface of thehousing and with the outer surface of the cable within said housing.

24. A connection as defined in claim 20 which comprises in additionelongated hollow sleeves formed of resilient elastomeric insulatingmaterial and having an annular chamber therein extending substantiallythe full length thereof, the radially outer walls of the axially innerends of said sleeves being tapered in conformity with the taper of therecesses in the ends of said voltage distributor and received therein insurface-to-surface contact, the interior of said chambers being chargedwith insulating fluid under pressure effective to press rounding theconductors to define a gap between the end of said insulation, connectormeans in the gap electrically interconnecting the bared conductor ends,a capacitive voltage distributor comprising an elongated tubular bodyformed of a dielectric having elongated tapered recesses extending intoopposite ends and having a central portion provided with a throughopening in which are located the bared conductor ends and the connectormeans, a generally tubular conducting housing having apertured end wallsthrough which the end portions of said cables extend, the space in eachend of said housing defined by the tapered wall of the recess in saidvoltage distributor, the outer surface of the cable, the end wall of thehousing, and the radially outer wall of the housing being filled by ahollow expansible sleeve portion formed of resilient elastomericmaterial having an elongated annular chamber therein extendingsubtantially for the full length of the portion of cable insulationexposed therein, said chamber being filled with insulating fluid atelevated pressure to insure full surface-to-surface pressure contactbetween the inner and outer surfaces of said sleeve portion and thecable insulation and the inner surface of said housing respectively.

27. A connection as defined in claim 26 comprising in .addition a secondsleeve portion extending axially outwardly from the outer end of eachfirst mentioned sleeve portion, said second sleeve portions forming theaxially outer ends of the annular chambers in said first mentionedsleeves and being formed of semiconducting material and shaped to formaxially tapered stress relief surfaces, the inner and outer walls ofsaid first mentioned sleeve portions being non-conducting.

28. A connection as defined in claim 27 in which both of said secondsleeve portions are also hollow and provided with annular chambersadapted to receive insulating fluid at elevated pressure to expand saidsecond sleeve portions into full surface-to-surface contact with theouter surface of said cables and the inner surfaces of said housing.

29. A high voltage electric connection comprising an elongated generallycylindrical housing having a side wall and an end wall provided with anopening through which extends the end portion of an insulated highvoltage cable, said cable having the end of its conductor bared at apoint remote from said end wall and having its insulation intact for asubstantial length of said cable within said housing, said housing andthe insulation of said cable defining therebetween an elongated annularspace, an elongated sleeve formed essentially of resilient, elastomericinsulating material occupying said space, said sleeve having anelongated annular chamber therein between radially inner and outerwalls, and

insulating fluid filling said chamber under elevated pressure sufficientto maintain the inner and outer walls of said sleeve in firmsurface-to-surface pressure contact respectively with the radially outersurface of the insulation of the end portion of said conductor receivedin said housing and theinner surface of the side wall of said housing.

30. An elongated insulating and stress relief sleeve construction foruse in a high voltage cable connection, said construction comprising afirst elongated sleeve section formed of resilient elastomericinsulating material provided with an elongated annular chamber thereinfor the reception of insulating fluid at elevated pressure, an endsection operatively connected to one end of said intermediate sectionformed of at least semi-conducting material, said first and end sectionshaving a tapered generally conical interface providing electrical stressrelief.

31. A construction as defined in claim 30 which comprises in addition asecond end section conforming to the definition of the first end sectionin claim 30 and operatively connected to the other end of said firstsection.

32. A construction as defined in claim 31in which said end section isformed of resilient elastomeric semiconducting material.

33. A construction as defined in claim 32 in which said end section isprovided with an elongated annular chamber therein for the reception ofinsulating fluid at elevated pressure.

1. A stress relief connection designed for application to insulated highvoltage electrical cable comprising a hollow tubular sleeve adapted tosurround the insulation adjacent the bared end of an insulated highvoltage electrical conductor and formed of resilient elastomericelectrically insulating material having at the end thereof remote fromthe bared conductor an inwardly tapered exterior surface, a generallytubular stress relief sleeve formed of a material which is at leastsemiconductive having an outwardly tapered interior end surface insurface-to-surface contact with the tapered exterior surface of saidhollow sleeve, a rigid support housing surrounding said hollow sleeve,the interior of said hollow sleeve being an elongated annular chamberadapted to be charged with a pressurized insulating fluid to expand theinner wall of said hollow sleeve radially inwardly to establish intimatecontact between the inner surface of said hollow sleeve and the outersurface of the insulation surrounding the conductor adjacent its baredend.
 2. A connection as defined in claim 1 in which said hollow sleeveis provided with inlet and outlet valves to provide for purging thehollow interior of the sleeve and to fill the hollow sleeve with fluidunder pressure.
 3. A connection as defined in claim 1 in which saidtubular stress relief sleeve is formed of resilient elastomeric materialand is also hollow to have an elongated annular chamber to receiveinsulating fluid under pressure.
 4. A connection as defined in claim 3in which passages are provided connecting the hollow interior of saidhollow tubular sleeve and the hollow interior of said stress reliefsleeve.
 5. A connection as defined in claim 1 in which said hollowtubular sleeve is filled with insulating fluid and permanently sealed.6. A connection as defined in claim 5 in which said connection comprisesan enclosing wall movably associated with said housing, and means formoving said wall relative to said housing to apply pressure to saidhollow tubular sleeve.
 7. A connection as defined in claim 1 in whichsaid fluid is an insulating liquid.
 8. A connection as defined in claim1 in which said fluid is an insulating gas.
 9. A connection as definedin claim 1 in which said connection is a cable termination, and in whichsaid housing comprises a hollow insulator body, comprising connectormeans exposed at the end of said body adapted to be electricallyconnected to the bared end of the conductor.
 10. A connection as definedin claim 1 in which said connection is for connecting the ends of twoinsulated high voltage cables, comprising means within said hollowtubular sleeve adapted to electrically connect the bared ends of theconductors, and in which the opposite ends of said hollow tubular sleeveare both tapered as aforesaid, and stress relief sleeves as aforesaidare provided at both ends of said hollow insulated sleeve.
 11. Anelectrical connection comprising in combination a high voltage cablehaving a conductor surrounded by insulation, the conductor having an endexposed and extending beyond the end portion of the insulation, a rigidhousing surrounding the end portion of the insulation, a hollow tubularresilient elastomeric sleeve having an elongated annular chamber thereininterposed between the end portion of the insulation and the housing,said sleeve having at the end thereof remote from the bared conductor atapered exterior surface, a generally tubular stress relief sleeveformed of a semi-conductive material having at an end thereof a taperedinterior surface in surfac-to-surface contact with the tapered exteriorsurface at said hollow tubular sleeve, an insulating fluid in thechamber in said sleeve under an elevated pressure sufficient to expandthe chamber defined by the hollow interior of said sleeve to force theinner wall thereof into firm surface-to-surface contact with saidinsulation.
 12. A connection as defined in claim 11 in which said hollowsleeve is provided with inlet and outlet valves to provide for purgingthe hollow interior of the sleeve and to fill the hollow sleeve withfluid under pressure.
 13. A connection as defined in claim 11 in whichsaid tubular stress relief sleeve is also hollow and has an annularchamber to receive insulating fluid under pressure.
 14. A connection asdefined in claim 13 in which passages are provided connecting thechamber in said hollow tubular sleeve and the chamber in said stressrelief sleeve.
 15. A connection as defined in claim 11 in which saidhollow tubular sleeve is filled with insulating fluid and permanentlysealed.
 16. A connection as defined in claim 15 in which said connectioncomprises an enclosing wall movably associated with said housing, andmeans for moving said wall relative to said housing to apply pressure tosaid hollow tubular sleeve.
 17. A connection as defined in claim 11 inwhich said connection is a cable termination, and in which said housingis in the form of a hollow insulator body, comprising connector meansexposed at the end of said body adapted to be electrically connected tothe bared end of the conductor.
 18. A connection as defined in claim 11in which said connection is for connecting the ends of two insulatedhigh voltage cables, comprising means within said hollow tubular sleeveadapted to electrically connect the bared ends of the conductors, and inwhich the opposite ends of said hollow tubular sleeve are both taperedas aforesaid, and stress relief sleeves as aforesaid are provided atboth ends of said hollow insulated sleeve.
 19. An insulated connectionbetween two high voltage cables having end portions in which baredconductor ends project beyond the ends of insulation surrounding theconductors to define a gap between the end of said insulation, connectormeans in the gap electrically interconnecting the bared conductor ends,a capacitive voltage distributor comprising an elongated tubular bodyformed of a dielectric material having elongated tapered recessesextending into opposite ends and having a central portion provided witha through opening in which are located the bared conductor ends and theconnector means, an inner conducting tube in said opening in contactwith said connector means, an outer elongated conducting tube coveringthe outer surface of the voltage distributor, a series of shortcircumferentially spaced, axially staggered conducting rings extendingalong and around each of the tapered recesses, said rings overlappingadjacent rings and spaced radially of each other, the rings beingentirely embedded in said dielectric body and having the spaces betweenadjacent rings being filled with the dielectric material of said body.20. A connection as defined in claim 19 which comprises in addition anouter housing formed of conducting material in contact with said outertube.
 21. A connection as defined in claim 20 in which said cables haveconducting shields extending into the housing, and means electricallyconnecting said shields to said housing.
 22. A connection as defined inclaim 21 in which the means connecting the shields and housing comprisesemi-conducting resilient sleeves in the ends of said housing in surfacecontact with said shields.
 23. A connection as defined in claim 22 inwhich said semi-conducting sleeves have annular pockets formed therein,and insulating fluid in said pockets at elevated pressure to expand thesleeves in full surface-to-surface contact under pressure with the innersurface of the housing and with the outer surface of the cable withinsaid housing.
 24. A connection as defined in claim 20 which comprises inaddition elongated hollow sleeves formed of resilient elastomericinsulating material and having an annular chamber therein extendingsubstantially the full length thereof, the radially outer walls of theaxially inner ends of said sleeves being tapered in conformity with thetaper of the recesses in the ends of said voltage distributor andreceived therein in surface-to-surface contact, the interior of saidchambers being charged with insulating fluid under pressure effective topress the inner walls of said sleeves surrounding said chambers intosurface-to-surface pressure contact with the insulation surrounding theend portions of said cables within said housing.
 25. A connection asdefined in claim 24, the axially outer end walls of said chambers havingstress relief annular surfaces tapered radially inwardly and axiallyoutwardly from the cable ends, the material of said end walls beingsemi-conductive.
 26. An insulated connection between two high voltagecables having end portions in which bared conductor ends project beyondthe ends of insulation surrounding the conductors to define a gapbetween the end of said insulation, connector means in the gapelectrically interconnecting the bared conductor ends, a capacitivevoltage distributor comprising an elongated tubular body formed of adielectric having elongated tapered recesses extending into oppositeends and having a central portion provided with a through opening inwhich are located the bared conductor ends and the connector means, agenerally tubular conducting housing having apertured end walls throughwhich the end portions of said cables extend, the space in each end ofsaid housing defined by the tapered wall of the recess in said voltagedistributor, the outer surface of the cable, the end wall of thehousing, and the radially outer wall of the housing being filled by ahollow expansible sleeve portion formed of resilient elastomericmaterial having an elongated annular chamber therein extendingsubtantially for the full length of the portion of cable insulationexposed therein, said chamber being filled with insulating fluid atelevated pressure to insure full surface-to-surface pressure contactbetween the inner and outer surfaces of said sleeve portion and thecable insulation and the inner surface of said housing respectively. 27.A connection as defined in claim 26 comprising in addition a secondsleeve portion extending axially outwardly from the outer end of eachfirst mentioned sleeve portion, said second sleeve portions forming theaxially outer ends of the annular chambers in said first mentionedsleeves and being formed of semi-conducting material and shaped to formaxially tapered stress relief surfaces, the inner and outer walls ofsaid first mentioned sleeve portions being non-conducting.
 28. Aconnection as defined in claim 27 in which both of said second sleeveportions are also hollow and provided with annular chambers adapted toreceive insulating fluid at elevated pressure to expand said secondsleeve portions into full surface-to-surface contact with the outersurface of said cables and the inner surfaces of said housing.
 29. Ahigh voltage electric connection comprising an elongated generallycylindrical housing having a side wall and an end wall provided with anopening through which extends the end portion of an insulated highvoltage cable, said cable having the end of its conductor bared at apoint remote from said end wall and having its insulation intact for asubstantial length of said cable within said housing, said housing andthe insulation of said cable defining therebetween an elongated annularspace, an elongated sleeve formed essentially of resilient, elastomericinsulating material occupying said space, said sleeve having anelongated annular chamber therein between radially inner and outerwalls, and insulating fluid filling said chamber under elevated pressuresufficient to maintain the inner and outer walls of said sleeve in firmsurface-to-surface pressure contact respectively with the radially outersurface of the insulation of the end portion of said conductor receivedin said housing and the inner surface of the side wall of said housing.30. An elongated insulating and stress relief sleeve construction foruse in a high voltage cable connection, said construction comprising afirst elongated sleeve section formed of resilient elastomericinsulating material provided with an elongated annular chamber thereinfor the reception of insulating fluid at elevated pressure, an endsection operatively connected to one end of said intermediate sectionformed of at least semi-conducting material, said first and end sectionshaving a tapered generally conical interface providing electrical stressrelief.
 31. A construction as defined in claim 30 which comprises inaddition a second end section conforming to the definition of the firstend section in claim 30 and operatively connected to the other end ofsaid first section.
 32. A construction as defined in claim 31 in whichsaid end section is formed of resilient elastomeric semi-conductingmaterial.
 33. A construction as defined in claim 32 in which said endsection is provided with an elongated annular chamber therein for thereception of insulating fluid at elevated pressure.